Frontiers’ journals are published exclusively online, with new articles published on a rolling basis. Articles appear on the journal’s main page, as per below example, with links to the full article content and images, accessible at no cost, anytime, and to any reader worldwide.
Frontiers also publishes e-Books arising from Frontiers Research Topics – which are collections of published articles on a focused theme. These can be downloaded for free as PDF or EPUB files from the Research Topic page as highlighted in below image.
Note that not all Research Topic have eBook. The below link allow you to search over all the Research Topics that have eBooks as shown below.
Alternatively, Research Topic Books (e-Books) can also be search with the below link and as illustrated below.